Valve-gear for steam-engines



(No Modl.)

L. D. DAVIS.

VALVE GEAR FOR STEAM ENGINES. No. 461,406 Patented Oct. 13, 1891.

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UNITED STATES 'AATENT OFFICE.

LEONARD D. DAVIS, OF ERIE, PENNSYLVANIA.

VALVE-G EAR FOR STEAM-ENGINES.

SPECIFICATION forming part of Letters Patent No. 461,406, dated October 13, 1891. Application filed February lfi, 1891- Serial No. 331,499. (No model.)

To all whom it may concern:

Be it known that I, LEONARD D. DAVIS, a

"citizen of the United States, residing at the city of Erie, in the county of Erie and State of Pennsylvania, have invented certain new and useful Improvementsin Valve-Gear for Steam- Engines; and I do hereby declare the following to be a full, clear, and exact descrip-' tion of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters of reference marked thereon, forming part of this specification.

My invention consists in the improvements in valve-gear for steam-engines, hereinafter set forth and explained, and illustrated in the accompanying drawings, in which Figure 1 is an end view of a marine engine embodying my improved valve-gear. Fig. 2 is a detail view of a portion of thelink mechanism. Figs. 3 and 4 are views illustrative of the operation of my invention.

Like letters refer to like parts in all thefigures.

In the construction of my invention shown in the drawings, Ais the frame of the engine,

B the cylinder, 0 the steam-chest, D the valve,

E the main shaft, F the connecting-rod, G the guides, and H the piston-rod, all of usual and ordinary construction.

On the shaft E, I secure an eccentric I, upon which I secure an eccentric-strap J in any convenient manner. 011 the opposite sides of the eccentric-strap J, I make bearings a and b, and upon a standard cl, secured to the base of the frame A, I pivot on a bearing 6 thereon a horizontal lever 6, preferably at about the center thereof. One end of said arm e I pivot upon the bearing a on the eccentric-strap J, and the other to the center of the link f, upon which the connecting-rod K of the valve-rod L works. To the central portion of the link f I secure a radial arm g of substantially the same length as the distance between the bearings a and b on the eccentricstrap J, and to the end of the arm 9 is pivoted one end of a connecting-bar h,which extends to and has its opposite end pivoted to the bearing b on the eccentric-strap J, so that the rotation of the shaft E and the eccentric I thereon in the eccentric-strap J operates through the lever e and the connecting-bar h, pivoted to the eccentric-strap J, to produce two movements of the link 71. simultaneously, one vertical and the other a tipping movement, as illustrated by dotted lines in Fig. 1 and also in Figs. 3 and 4. These move opened and then slower until immediately before closing the port, when it again moves quickly, gives me also at all ordinary points of cut-off a very free exhaust, as the slow movement of the valve during the intermediate portion of its traverse holds the exhaust fullyopen during that time. For varying the cut-off and reversing the valve movement I mount a rock-shaft M on the frame A, and to a crank-arm m thereon I pivot a rod N, the opposite end 72 of which is pivoted to the valveconnecting rod K, so that the end Z of the valve-connecting rod K can be moved to any desired point on the link f for varying the cut-off or for reversing the engine.

I have shown and described a simple and convenient mechanism for utilizing my invention; but I do not confine myself to the exact construction shown and described. Therefore,

Having fully described my invention so as to enable others to construct and use the same, what I claim as new, and desire to secure by Letters Patent of the United States, is

1. The combination, in a steam engine valve-gear, of a link and an eccentric-strap, with a lever mounted in a bearing on the engine-frame and also a connecting-bar coupling said link to opposite sides of the eccentric-strap, substantially as and for the purpose set forth.

2. The combination, in a steam-engine valve-gear, of an eccentric-strap and a link having an arm projecting radially therefrom, with a lever mounted in a bearing upon the engine-frame and having one end thereof pivoted to the eccentric-strap, and a connectingbar, one end of whichis pivoted to the end of the arm on the link and the other to the opposite side of the eccentric-strap, substantially as and for thepurpose set forth. v

3. The combination, in a steam engine Valve-gear,of a link, an eccentric-strap, alever mounted in a bearing on the engine-frame, and also a connecting-bar coupling said link to opposite sides of said eccentric-strap, with a valve-connecting rod operating on said link, and lever mechanism connected with said valve-connecting rod for moving the valveconnecting rod on said link to vary the cutoff or reverse the engine, substantially as and for the purpose set forth.

4. The combination, in a steam engine valve-gear, of a link having a radial arm thereon, and an eccentric-strap having bearings a and b atopposite sides thereof, with a lever mounted in a bearing on the engineframe and coupled at one end to the bearing a on the eccentric-strap, the other end thereof being coupled to the central part of and supporting said link, and a connecting-bar, one end of which is coupled to the radial arm on the link and the other end to the bearing b on the eccentric-strap, substantially as and for the purpose set forth.

In testimony whereof I aifix my signature in presence of two witnesses.

' LEONARD D. DAVIS. Witnesses:

L. D. HANFORD, W. J. THOMAS. 

